Re: mirrored machines via network

Ray Lehtiniemi (
Fri, 1 Nov 1996 19:55:18 -0500 (EST)

On Fri, 1 Nov 1996, James R. Leu wrote:

> operations of a small ISP. I am looking into ways of implementing redundant
> servers.
> The idea I have, necessitates two main developments. The first of which is
> a "intelligent" name-server. I have begun development of this already. I have
> started by using th bind-4.x.x source. The end result will hopefully be a
> name-server that checks if a machine is responding, before it gives out the IP

how about clients who use nonauthoritative answers from caching servers
elsewhere on the net?

> Last but not least, if anyone has seen this or anything similar, please let me
> know. I looked long and hard for something similar, but I'm sure my search

there is a product called openvision (i believe now called axxion
something) that does this. i don't recall the vendor offhand. they have
two machines connected via a private network, and share a pair of IP
addresses on their public network interfaces. the active pings the
standby witha UDP heartbeat. if the standby stops getting heartbeats, it
reboots the active, swaps IP addresses, and becomes the active. dunno how
they tell everyone else the change in physical to IP address mapping.
apparently it works for ethernet but not fddi public interfaces.

you can get some funky software to work with this called disksuite. it
shares a scsi bus between the two machines so you get the exact disk
state at the time the active died. dunno how they do that.

Ray Lehtiniemi <>